The Cardiology Transgenic and Knockout Core Facility was created in 1998 to serve the needs of investigators within the Cardiology Division and to foster collaborations outside the Division. Although other transgenic core facilities exist at the University of Pennsylvania, these facilities are in heavy demand and waiting time commonly averages several months before injection of constructs. Therefore, the Cardiology division committed significant divisional resources towards the establishment of a fully functional core within Cardiology that could promptly and efficiently serve the needs of divisional investigators. The Molecular Cardiology Transgenic and Knockout Core generates transgenic mice through DNA injection of oocytes and knockout mice through ES cell injection into btastocysts. The continued heavy use of other University transgenic facilities continues to make this independent core extremely valuable to the timely progression of our research efforts. Since many of the projects proposed in this program rely upon the creation of multiple transgenic and knockout mice, prompt service from a successful Transgenic Core will be ssential to the success of this program.